noun
dead of night; middle of the night
Refers to the deep, quiet hours of the night, often with a spooky or eerie connotation. In modern usage, it is a literary or traditional expression rather than a precise time.
丑三つ時になると、古い屋敷から不思議な音が聞こえるという。
They say that at the dead of night, strange sounds can be heard from the old mansion.
丑三つ時の静けさが怖かった。
The silence of the middle of the night was frightening.
noun
third quarter of the hour of the ox (approx. 2:00–2:30 AM)
Historical timekeeping term. In the traditional Japanese temporal system, the hour of the ox (丑の刻) was divided into four quarters; the third quarter was considered especially inauspicious and associated with supernatural events.
See also: 丑の刻
丑三つ時は、丑の刻の第三刻にあたる。
Ushimitsudoki corresponds to the third quarter of the hour of the ox.
昔話では、丑三つ時に妖怪が現れるとされる。
In old tales, monsters are said to appear at the third quarter of the hour of the ox.